In prior art structure, a base (5), as a shell, receives a lamp at its opened side and a pair of conductive slices (6), (7) which are inserted into the base from two grooves on the closed side of the base. As shown in FIG. 5, the prior assembly of the lamp and the base, it can be seen that one conductive slice (6) leans against the inner wall of the base (5) and the other slice (7) has its inner end being folded to a perpendicular manner. Since the conductive slice (6) may not lean closely against the wall of the base (5), such as in the position of the dot line of FIG. 5, it could disturb the procedure of assembling the lamp into the base (5). And the perpendicular part of the slice (7) is possibly inclined, that contacts the head of the lamp which might not be a well engaged situation.